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package scalac.transformer.matching ;
import scalac.* ;
import scalac.symtab.Symbol ;
import scalac.symtab.Type ;
import scalac.symtab.Definitions ;
import scalac.symtab.Modifiers;
import scalac.ast.Tree;
import scalac.ast.TreeGen;
import scalac.util.Name;
import scalac.util.Names;
import Tree.*;
import scalac.transformer.TransMatch.Matcher ;
import java.util.* ;
import ch.epfl.lamp.util.Position;
public class Autom2Scala {
protected boolean optimize = true;
static final Name HASNEXT = Name.fromString("hasnext");
static final Name CURRENT_ELEM = Name.fromString("cur");
final int FAIL = -1;
DetWordAutom dfa;
protected CodeFactory cf;
Definitions defs;// cf.defs only for convenience
TreeGen gen; // cf.gen only for convenience
/** owner of the pattern matching expression */
protected Symbol owner;
/** symbol of the matcher DefDef or Label */
Symbol funSym;
/** symbol of the iterator ( scala.SequenceIterator ) */
Symbol iterSym;
/** symbol of the switching result ( scala.Int ) */
Symbol resultSym;
/** symbol of the state variable ( scala.Int ) */
Symbol stateSym;
/** symbol of variable holding current label */
Symbol curSym;
/** symbol of boolean variable that indicates we have not reached end of sequence */
Symbol hasnSym;
protected Type elementType;
public int pos;
Type funRetType() {
switch( funSym.type() ) {
case MethodType( _, Type retType ):
return retType;
}
throw new RuntimeException();
}
Tree callFun( Tree[] args ) {
return gen.mkApply_V(gen.Ident(pos, funSym), args);
}
public Autom2Scala( DetWordAutom dfa,
Type elementType,
Symbol owner,
CodeFactory cf ) {
this.dfa = dfa;
this.elementType = elementType;
this.defs = cf.defs;
this.gen = cf.gen;
this.owner = owner;
this.pos = Position.FIRSTPOS;
this.cf = cf;
this.am = new AlgebraicMatcher( cf.unit );
}
// overridden in RightTracerInScala
Tree loadCurrentElem( Tree body ) {
return gen.mkBlock( new Tree[] {
cf.gen.ValDef( this.hasnSym,
cf._hasNext( _iter() ) ),
cf.gen.ValDef( this.curSym,
gen.If( gen.Ident( pos, hasnSym ),
cf._next( _iter() ),
gen.mkDefaultValue(cf.pos,curSym.type())))},
body );
}
/** bug ?? */
Tree currentElem() { return gen.Ident( cf.pos, curSym ).setType( curSym.type() ); }
Tree currentMatches( Label label ) {
switch( label ) {
case TreeLabel( Tree pat ):
return _cur_match( pat );
case SimpleLabel( Tree.Literal lit ):
return cf.Equals( currentElem(), lit );
}
throw new ApplicationError("expected either algebraic or simple label:"+label);
}
//
// translation of automata to scala code
//
/** `<switchResult>' */
public Tree _swres() { return gen.Ident( pos, resultSym );}
/** `<state>' param */
public Tree _state() { return gen.Ident( pos, stateSym ); }
/** `<iterator>' param */
Tree _iter() { return gen.Ident( pos, iterSym ); }
/** simple optimization: if we are in a sink state, stop traversing sequence
*/
Tree stateWrap(int i) {
if( dfa.isSink( i ))
return run_finished( i ); // state won't change! optimization
else
return gen.If( cf.Negate( gen.Ident( pos, hasnSym )),
run_finished( i ),
code_state_NEW( i ));
}
/** body of the matcherDefFun
*/
public Tree code_body_NEW() {
int[] tags = new int[dfa.nstates];
Tree[] bodies = new Tree[dfa.nstates];
for( int i = 0; i<dfa.nstates; i++ ) {
tags[ i ] = i;
bodies[ i ] = stateWrap( i );
}
if( optimize )
return loadCurrentElem( gen.Switch( _state(),
tags,
bodies,
code_error(), // cannot happen
funRetType()));
Tree res = code_error();
for( int i = dfa.nstates-2; i>= 0; i-- )
res = gen.If( cf.Equals( _state(), gen.mkIntLit( cf.pos, i )),
bodies[ i ] ,
res );
return loadCurrentElem( res );
}
AlgebraicMatcher am;
/*
void handleVars( ) {
}
*/
// calling the /*AlgebraicMatcher*/PatternMatcher here
Tree _cur_match( Tree pat ) {
Matcher m = new Matcher( this.funSym, /* owner*/
currentElem(), /* root */
defs.BOOLEAN_TYPE() /* restype */);
am.construct( m, new CaseDef[] {
cf.gen.CaseDef( pat,
gen.mkBooleanLit( pat.pos, true )),
cf.gen.CaseDef( cf.gen.Ident(pat.pos, defs.PATTERN_WILDCARD),
gen.mkBooleanLit( pat.pos, false )) },
false);
return am.toTree();
}
Tree code_delta( int i, Label label ) {
throw new RuntimeException();
}
/** some error happened which is due to bug in translation/automaton
*/
final Tree code_error() {
return gen.mkBlock(
gen.Console_print( pos, "System error during pattern matching. Please file bug report\n"),
cf.ThrowMatchError( pos, funRetType() )
);
}
Tree code_fail() {
return gen.mkIntLit(Position.FIRSTPOS, FAIL );
}
/** code for the return value of the automaton translation
*/
Tree run_finished( int state ) {
if( dfa.isFinal( state )) {
return gen.mkIntLit(Position.FIRSTPOS, ((Integer) dfa.finals.get( new Integer( state ) )).intValue() );
}
return gen.mkIntLit( Position.FIRSTPOS, FAIL );
}
Tree code_state_NEW( int i ) {
Tree stateBody = code_delta( i, Label.DefaultLabel );
if( stateBody == null )
stateBody = code_fail();
HashMap trans = ((HashMap[])dfa.deltaq)[ i ];
for( Iterator labs = dfa.labels.iterator(); labs.hasNext() ; ) {
Object label = labs.next();
Integer next = (Integer) trans.get( label );
Tree action = code_delta( i, (Label) label );
if( action != null ) {
assert stateBody != null : "stateBody is null";
stateBody = gen.If( currentMatches((Label) label ),
action,
stateBody);
}
}
return stateBody;
}
}
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